Automatic telephone system



May s, 1928. 1,669,174

W. PlNELL AUTOMATIC TELEPHONE SYSTEM led Aug. 19. 1926 3 Sleek-Sheet 1 K l aF c470 Aj/{j/ 241m Avr rN- EPJ E HRz -Iuuen 01 May s, 1928. 1,669,174

W. PINELL AUTOMATI C TELEPHONE SYSTEM Filed Aug. 19. 1926 s Sheets-Sheet 2 zj-f am: am;

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Filed Aug. 1%, 192a AUTOMATIC TELEPFO May 8, 1928.

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Patented May 8, 1928.

' UNITED STATES a g 1,669,174 PATENT OFFICE.

waLrnnPrnELL, or enarirn, eaniiraiix ssienon 'ro stamens a iinnsirn AK'rInir- GESELLSCHAFT, or srniunnssranr BEI BERLIN, GERMANY.

AUToiirArrc TELEPHONE sY's'rEM.

Application'filed August 19,1926, Serial No. 130,127, and in Germany August 29,1925.

The present invention relates to a circuit arrangement for automatic telephone systems, .in which the selection of an idle line, which is to be used for the connection to be set up, is effected by in succession starting up several switches, which are connected in parallel to an incoming junction line, for the purpose of selecting an idle line. A' system of this type is disclosed in the British Patent #211,287, issued Jan. 7, 1925, to J. E. Ostline and \V. O. Passmore.

Now the present inventionrelates toa further development of the arrangement ac cording to the British patent, and it especially'relates to switches having several differently numbered groups of contacts. Over each of these differently numbered contact groups can be reached lines belonging to a particular trafiic direction. Now the object of the invention is to enable a free line to be selected in theparticular traflic direction determined by the positioning of the group selecting switch, even when thenumber of 'lines in the selected group is greater than the number of contacts for that group at the selecting switch. This is achieved by switching means, which function when all the lines accessible over this particular con tact group are engaged, and the said means start up a hunting switch, which ,is likewise connected to the incoming junction line and has connected to it other lines outgoingin the desiredtraflic direction.

In the Figures 13 are shown several examples of the invention, the circuit arrangements of which will now be described indetail.

The Figure 1 shows an example, in which. connections to one traflic direction are set up over the fourth contact group of a group selector I.GW1 and the number of lines out going in thls traffic direction is greater than the number of contacts in the'fourth contact group at the selector LGWVl.

The test lead of each junction line con tains a resistance Rythepurpose of this will be explained hereafter. An end bank contact is directly earthed, and when the wiper of IGlVl reaches'thisbank contact, a

switchingover is to take place to *a second hunting switch connected in parallel with lLGiVlto the incoming junction line. The

from the relays in the switches. When the incoming junction line is taken into use, the

relay A1 is operated over its 'lo'op, further-- more the relays T1 and C1 are energized over: earth, T1, c-lead, contact 1m1, wind-' ing of the slowv actingrelay G1, Off normal contact 2A1, battery, earth, and parallel to winding'of C1 over aresistance winding iof the relay C1, battery, earth. The energiz-y ing of the winding C1 causes the relay C1 to operate and it closes the following cir'-; cuit: earth, contact 801, relay winding C2, relay V2, relay V1, battery, earth. The im pulses'received bythe relay A1 cause it to alternately operate its contact 4c1in known manner. The relay V1 closes a circuit for the lifting magnet H1 over earth, contact 5111, back contact Gal, magnet 7L1, back contact 7e01, battery,earth. The contact 6 gives the lifting magnet H1 the impulses for lifting in known manner controlled by the number dial. The selector is rotated overthe desired contact group in known manner over earth, contact 8421,.back'contactQoQ,

rotary magnet D1, back contact 10751, ofi' normal contact 11701, interrupter U1, bat tery, earth. When the selector finds an idle line the test relay P1 operates and opens the circuit of the rotary magnet. The test relay P1 is energized over earth, resistance R, segment and wiper of I.GlV1, co1itact 2301, winding PlII, winding P11, relay l-lRl, battery, earth- Thecontact'24p1 in known manner short circuits the Winding of P1. The resistanceR is given' suchjamagf nitude that'the relay I-IRI cannot be operated even when the winding P11 is short circuited.

Should, however. the selector fail to find an idle outgoing line during the1hunting movement over the contact group, it will finally reach the end back contact, whichis directly connected toearth, as aloc'ivemen tioned; .The relay HRl can' now beeperated over the above mentionedcircuitand at its contacts 197241 and 207ml, it switches the incoming junction. line over to the hunt ing switch FVVl located in parallel there with. The relay HRl at its contact ltitrl closes 'anenergizingcircuit for the rotary magnet D2of the switch FWl as follows earth, contact 147ml, oft normal contact; 157132, rotary magnet D2, back contact 16152, battery, earth. When the swit ch FWl} i started upgthe rotary switched i that in the Figure 1.

over to the self interrupter U2- over the oli normal contact 15702. The switch FlVl is now tested by the test relay P2 in the same manner as that described above, and it arrests the switch on the first disengaged junction line in the outgoing traiiic direction by opening the contact 16292. The incoming junction line is now switched through to this line at the contacts ;?2 and 26;)2. At

I the end of the conversation, both switches when all the outgoing lines are engaged, and

the incoming junction line is directly switched over to the hunting switch FWQ. connected to in parallel with the switch IGW2. The selector ICE/V2 is started up on the origination of a call in the same manner asthat described above. Each outgoing junction line is provided with a relay E1, E2, etc, the contacts 5561, 5662, etc. of which close a circuit for energizing the busy relay BR. When all the outgoing junction lines IV LGl VQ are engaged, the relay BR is energized and then prepares the circuit for the winding I or the relay The circuit for this. winding is closed by a multiple contact, 152m7cIV as soon as the switch has reached the wanted contact group, for example the-fourth group. If all the lines of thiscontact group be engaged, the closing oi? the contact 5461' completes the circuit of the winding HR2I, and the switching over to the'hunting switch FiV2 is effected at the contacts 467L1 2. At the same time the contact .llhTQ closes a circuit for the release magnet M2, which causes the LGVV2 to release immediately. The auxiliary relay HR2 finds a locking circuit over earth, contact 49425, contact 507L1 2, winding HR2II, battery, earth. The relay H112 is made slow acting, so that the magnet H2 cannot operatewrongly when the relay V5 works irregularly. Here likewise the hunting'switch is released in known'manner at the end of the,- conversation.

Figure 3 shows the arrangement of two switches FVV8 and FlV i, which are parallel to different contact groups of the selector I.GW3. It is meant to represent the possibility of connecting up a large number of groups of lines going indiiierent directions from a group selector. The line group contacts for each group of lines going in 2.

particular direction are represented by I and H. This circuit arrangement also requires only a single test relay P The method of operating will now be described. The selector LGWil is taken into use in the manner already described above. If a subscriber wishes to set up a connection in the traffic direction reached over the contact group I, and the LGi 3 has found all lines engaged, the relay H113 is brought into action, by the contact 741031 which is an end bank contact of the first contact group. On reaching the first contact group, the contact 77 271701 was closed, hence the rotary magnet D5 of the hunting switch FVVB is now closed over earth, contact 767ml, contact 777127111, off normal contact 7 8%, rotary magnet D5, contact 8137i. battery, earth. When an idle junction line is reached. the switch is arrested by the opening of the contact 8131i. At the same time the incoming junction line is switched through to this idle line owing to the closure er the contacts 8279a and 88214. The operation of the relay H113 caused the contacts 847L9 3 and 85714 3 to be switched over to the switches FY1 23 and FNei, which are located in parallel. On energizing, the relay HR3 moves its contact 62hr?) into its operated position, this opens the circuit of the lifting and rotary magnets of TGlVZ-l and closes the circuit of the release magnet hi3, thereby returning the IGVV?) to its normal position.

Ifthe subscriber, now wishes to make a call in the traiiic direction reached over the second contact row or lGlVii, and it all the lines in this contact group be engaged, the switchingover to the hunting switch FW L takes place, because when the contact T510311 reached, the multiple contact 79mlill is closed. while the contact Timicl remains open. Hence the rotary niagnetD-(i of the hunting switch Five is energized and it actuates this switch in the same manner as above described. At the end of the conver sation, the connection is released in known manner. a

hat is claimed is:

1. In a telephone system, a main and a branch exchange, a group or lines connect ing said main and branch exchanges, a numerical selector having access to said group for extending calls from the main to the branch exchange, a second group of lines connecting said main and branch exchanges, a hunting switch having access to said second group and connected in parallel with said selector, and means for operating said hunting switch to hunt for an idle line in the second group when all the lines in the first group are busy.

2. In a telephone system, a main and a branch exchange, a group oflines connecting said main and brench exchanges, a numerical selector having access to said group lUU ees-s74 i and means whereby said test relay tests the 2 lines accessible to both said selector and said hunting switch.

3. In atelephone system, a main and a branch exchange, a group of lines connectin said main and branch exchanges, a selector having access to said group, means for operating said selector to select said group, means for operating said selector to hunt for an idle'line in said group, a second group of lines connecting said main and branch exchanges, a hunting switch associated with said selector and having access to said second group, means for operating said hunting switchwhen all the lines" in said first group are busy, and means responsive to said selector selecting said first group when all the lines therein are busy for automatically releasing said selector.

4. In a telephone system, a main and a branch exchange, a group of lines connecting said main and branch exchanges, a selector having access to said group, means for oper- -ating said selector to select said group,

means for operating said selector to hunt for an ldle hne in said group, a second group 7 of lines connecting said main and branch exchanges, a hunting switch associated with said selector and having access to'said second group, 'ineans for operating said hunting switch when all the lines in said first group are busy, and means responsive to said selector selecting said first group when all said lines therein are busy for preventing the hunting operation of said selector.

5. In a telephone system, a main and a branch exchange, a group of lines connecting said main and branch exchanges, a selector having access to said group, means for operating saidselector to select said group, means for operating said selector to hunt for an idle line in said group, a second, group of lines connecting said main and branch exchanges, a hunting switch associated with said selector and having access to said second group, means for operating said hunting switch when all the lines in said first group are busy, and'means responsive to said ,selector selecting said first group when all said lines therein are busy for automatically releasing said selector and for preventing the hunting operation of said selector.

6. In a telephone system, a main and a branch exchange, a group of lines connecting said main and branch exchanges, a selector having access to said group,means for operating said selector to select said I group,

means for operating said selector to hunt for an idle line in said group, a second group of lines connecting said main and branch exchanges, a hunting switchfhaving access to said second group, a chain relay associated with the test terminal of each of the lines in said first group, me'ans'for energizing said relays when their; associated lines are busy, a group busy relay, contacts on said chain relays for closing an energizing for said busy'relay, a switching relay in said selector, contacts on said busy relay for pre- 7 paring anenergizing circuit for-said switching relay, a switching device in said selector operated responsive to th'e'operation of said selector to said group for completing the circuit for saidcswitching relay, and "contacts on saidswit'ching relay for switchingover the incoming leads of saidselector to said hunting switch and for causing the opera tion of said hunting switch. a

7. In a telephone; system, a main and a branchexchange,a group of lines connect ing said main and branch exchanges, a selector having access to said group', means 'for operating said selector to select said group, means for operating said selector to hunt for an idle hne in said group, a second group of lines connecting said main and branch exchanges, a hunting switch having access to said second group. a chain relay associated with the test terminal of each of the lines in said first group, means for energizing said relays when their associated lines are busy, a group busy relay, contacts on said chain relays for closing an energizing for said busy relay, a switching relay in said selector, contacts on said busy relay for preparing an energizing circuit for said switching relay, a switching devlce in said selector operated responsive to the opera tion'of said selector to said group for completing the circuit for said switching relay, and contacts on said switching relay for switching over the incoming leads of said selector to said hunting switch for causing the operation of said hunt-ing switch and for preventing the hunting operation of said selector.

8. In a telephone system, a main and a branch exchange, a group of lines connecting said main and branch exchanges. a selector having access to said group, means for operating said selector to select said group,

means for operating said selector to hunt for an idle llne in said group, a second group of lines connecting Silld'lllttlll andcbranch exchanges, a hunting switch having access ill) said selector, contacts on said busy relay for preparing an energizing circuit for said switching relay, a switching device in said selector operated responsive to the operation of said selector to said group for completing the circuit for said switching relay, and contacts on said switching relay for switching over the incoming leads of said selector to said hunting switch, for causing the operation of said. hunting switch, for preventing the hunting operation of said selector, and "for closing a circuit {or releasing said selector.

9. In a telephone system, a main and a branch exchangaa group of lines connecting said main andln'anch exchanges, a selector having access to said group, means for operating said selector to select said group. means for operating said selector to hunt for an idle line in said group, a second group of lines connecting said main and branch exchanges, a hunting switch liavii'ig access to said second group, a switching relay in said selector, in ans {oroperating said relay responsive to the operation of said selector to said group when all the lines in the first group are busy, and contacts on said relay for causing the operation of said hunting switch and for preventing the hunting mg said main and branch exchanges, a selector having access to said group, means for operating said selector to select said group, means for operating said selector to hunt for an idle line in said group, a second group of lines connecting said main and branch exchanges, a hunting switch having access to said second group, a switching re lay in said selector, means Ior operating said relay responsive to the operation of said solector to said first group when all the lines in tl e first group are busy, and contacts on said relay for causing the operation of said hunting switch, {or preventing the hunting operation of said selector, and for closing a circuit to release said selector.

In witness whereof, I hereunto subscribe my name this 26th day of July, A. D. 1926.

lVALTER PINELL. 

